Stabilization of oils



Patented May 12, 1942 STABILIZATION or OILS Sidney Musher, New York, N. Y., assignor to Musher Foundation Incorporated, New York, N. Y., a corporation of New York No Drawing. Application July 18,1940,

, Serial No. 346,145

9 Claims. (01. 260-3985) The present invention relates to the stabilization of glyceride oils and particularly to the stabilization against 'oxidative deterioration of those glyceride oils which contain a large proportion of unsaturated glycerides.

It has been found that these oils are particularly'oxidizable and that thisv deterioration is increased wherever the oils are subjected to high temperature deodorization during the refining process.

It has now been found that when such glyceride oils are heated to relatively high temperatures with finely divided de-oiled spice residues, instead of losing stability and becoming more subject to deterioration, the oils will become very stable and highly resistant to oxidative deterioration and rancidity.

The spice residues, and particularly clove and cinnamon residues, in finely divided and substantially oil exhausted form, are dispersed in the glyceride oil which is then heated or they may be added to the oil during high heat treatment to develop marked antioxygenic effectiveness.

For example, the essential and fixed'oils may be substantially removed from the spices by steam 1 distillation, expression or extraction and the residue thus obtained,-preferably finely divided to about 50 mesh and desirably to over 100 mesh, may be added to the oil' and heated therein.

The spice residue is added in an amount of less than 10% and desirably less than 2%. As little as 0.05% to 0.5% will give'highly desirable stabilizing results when the glyceride oils are treated in accordance with this invention.

After dispersing the spice residue in the oil, the oil is heated to an elevated temperature, desirably in excess of 250 F. and preferably to between 325 F. and 450 F. for at least 15 to 30 seconds.

It has been found that merely melting a glycfor eride fat or oil, particularly where the glyceride is solid'at room temperature, is not suflicient to give the desired efiect and it is necessary to utilize an elevated temperature substantially above the melting point of the glyceride if it normall be solid at room temperature. 1

During the heating period, the residue may become burnt or charred and, where. desired, the burnt residue may be removed as by filtration or centrifuging from the body of the oil, as the stabilization of theoil will already have been effected.

This charring apparently enhances the action of the spiceresidue on the oil and'it has been found particularly desirablefor the heating tube sufficiently high so as to produce charring in order to obtain the fully desirable resultsof the present invention.

. The oil which has been heated with the spice residue will be darker as the result of the elevated temperature treatment and the stabilization will have been effected even though the charred residue be removed from the oil as by filtration or centrifuging.

It, however, has been found that the original light color of the oil may be restored by a bleaching process as, for example, with fullers earth or other decolorizing materials and still retaining a substantial enhancement in the stability of the oil. 7

The results of the present invention are particularly surprising since antioxidants are recognized as losing atleast a portionof, andin most cases a major portion of their effectiveness when heated to elevated temperatures such as to 400 F. or more.

' Example I until rancidity as determined organoleptically and by peroxide values was observed. A sample of lard from the same lot to which 0.5% of clove residue was added but without being subjected to the 400 1. heat treatment was similarly tested along with a sample of the original untreated lard;with the following results.

Rancid after- Untreated lard 2' hours Lard containing 0.5%- clove residue p unheated 3% hours Lard containing 0.5% clove residue heated to 400 F. for 30 seconds, cooled and filtered 14 hours The glyceride may, where desired, be bleached or otherwise refined after treatment at'the elevated temperature with the spice residue and a distinct enhancement of the antioxygenic effect will be obtained, such enhancement being far in excess of normal expectation.

It is not desirable for the heating to be conducted in a small body of the oil and that oil used as a basefor addition to a largebody of oil. The most desirable method is for'the spice residue to be dispersed in the entire body of material to be stabilized, followed by subjecting the oil to a high heat in order to produce the desired interaction or result.

Apparently a chemical reaction occurs between certain components of the spice residue which may be placed into reactive condition by the de-oiling of the spice residue and the oil at the elevated temperature whereby the stabilization is effected, as this reaction does not appear to be related to ordinary negative oxidation catalysts by means of which antioxidants normally exercise activity.

The higher the temperature to which the oil containing the spice residue is subjected, the greater the stabilizing action although the sharpest increase in stabilization is between about 325 F. and 450 F.

Example II Bleached refined lard was prepared in the following manners:

Lard A.Untreated.

Lard B.1% of clove residue ground to about 50' mesh was dispersed therein, stirred for 5 minutes, and filtered.

Lard 'C.1% of clove residue was dispersed therein, heated to 200 F. for '5 minutes, and filtered. i

Lard D.1% of clove therein, heated to 300 F. tered. Lard E.--1% of clove therein, heated to 400 F. tered.

Lard F.1% of clove therein, heated to 450 F. tered. The lards were then tested for stability as in Example I with the following results:

Rancid aftereresidue was dispersed residue was dispersed for minutes, and filresidue was dispersed for 5 minutes, and fil- Lard A 1 hour Lard B 2 hours Lard C 2% hours Lard D 7 hours Lard E 23 hours Lard F 26' hours l The heat treatments need not be prolonged, the enhanced antioxygenic effect being obtained in relatively short periods particularly where the higher temperatures are employed. Normally,- the oil containing the spice residue may merely be heated to the desired temperature and allowed to cool, beingheld at the high temperature for a period of minutes or more.

The heattreatment will usually be carried out at atmospheric pressure but the use, of super or sub-atmospheric pressures may also be employed with satisfactory results. v V

This process may be utilized in the treatment and stabilization ofv a Wide variety of refined or crude glyceride oils such as the vegetable oils and fats including cottonseed oil, corn oil, peanut oil, linseed oil, soya bean oil, olive oil, etc., the animal oils and fats including lard,itallow, oleo oil, cod liver oil, halibut liver oil, mackerel oil, menhaden oil, herring. oil, shark liver oil, butter, etc.,the glyceride soap oils and the sulfonated oils.

This invention'is, however, particularly beneficial in the treatment of those glycerides' which contain large proportions of unsaturated fatty acids, as the spice residue appears'to react'more completely with these unsaturated oils at the -elevated'temperatures.

for 5 minutes, and fil- The spice residues should be finely ground or crushed as. for example, placed in flour form.

They may also be made into paste form by grind-.

whereby the necessary interaction is obtained.

Although the spice residues may already have some antioxygenic effect when added to the glyceride oils and without the heat treatment, nevertheless such antioxidant power is limited and is much less than the stabilizing efiect obtained after the addition of the spice residues and dispersion in the oil to be stabilized, followed by the heat treatment to over 250 F. and preferably to 325 F. to 450 F.

The stability of the treated oils will often be enhanced from 50% to 500% or more by the heat treatment in thepre'sence of these substances as compared to the stability which would be obtained by the addition of the residues withoutthe heat treatment described in this. invention.

The most important features of the present invention reside in the fact that the added material is not normally present in the oil or oxidizable material to be stabilized and upon addition is thoroughly dispersed in such oil. The heat treatment is carried out for a suflicient length of time to increase the stabilitylby usually not less than 50% over the stability of the unheated .oil.

As a preferred method for the heating, the .entire body of oil containing the spice residue thoroughly dispersed therein may be raised to the de-, sired temperature withagitation, maintaining a uniform'temperature throughout, and then permitted to remain at this temperature while agitating. The oil may then; be allowed to. cool without refrigeration.- V V 1 While'thespiceresidue is dispersed in the oil at theelevated temperature of about 400 vF. superheated. steam may,1where desired, be continuously injectedintothe oil over a period as long as 4 to 6 hoursand the objectionable flavors and odors originally present in the oil may be removed" therefrom while the spice residue is exerting its enhanced antioxygeniceifect.

It vhas been found particularly desirable for a small amount of spice residue to'be added to high fat containing animal products, heating at atmospheric or elevated pressures to temperatures of about 250 F. so that the glyceride oil or fat contained therein is released from the meat or fish animal product and 'a'highly stabilized animal glyceride is obtained. 7 V t For example, to a kettle of hog fat containing 70%, total glycerides may be added 0.5% of clove residue against the weight of the hog fat and the combination placed in va steam kettle with steam being injected into the kettle to produce about 40 pounds pressurer After a i4to 6 hourtreat ment, the pressure'may be released and the rendered lard removed. The stability. of. thelard obtained in this manner will be much greater than if the clove residue had merely been added to the lard afterrendering.

For example, when a small amount of a spice residue is added to hog fat and the hOg fat containing the spice residue is then rendered at a temperature of 275 F, for 4 hours, the rendered lard'removed from the rendering kettle has a far greater stability thanlwhere a proportionate amount of the spice residue is added to the lard after rendering and the improvement in stability is even greater than where the spiceresidue is added to the lard after rendering and the lard containing the spice residue is then heated to 275 F. for 4 hours. Apparently afurther interaction takes place by adding the spice residue to the rendering kettle where the rendering is conducted at over 250 F. resulting in a most highly stabilized oil.

In a similar manner, a small amount of spice residue may be added to the rendering'kettles in the rendering of other meat and fish oils and fats including tallow, menhaden oil, herring oil, etc., or to the cooking kettles in the manufacture of fish meals, particularly high glyceride containing fish meals, and where the temperature is at least about 250 F., the desired interaction will result producing enhanced stabilization.

Where the glyceride oils are heated over long periods to temperatures over 250 F. and desirably to temperatures over 300 F., small amounts of the spice residues may be added to the oils at regular intervals of 5 to 20 hours followed by filtration to remove the insoluble portion before adding a fresh amount of the spice residue. In this manner, the glycerides will be held in highly stabilized and non-rancid condition over very long periods.

One of the highly unsaturated glyceride oils that has been found particularly desirable for treatment in accordance with the present invention is the crude unrefined corn oil obtained from the hydraulic or expeller expression of drymilled corn germ and where neither the corn nor the corn germ has been subjected to steepingin sulphurous acid water prior to removal of the germ.

There may be added to the crude corn oil a small proportion of the spice residue followed by elevated temperature treatment of at least about tracted material remains substantially free of the solvent.

These extracts may be applied in the manner analogous to that described above for the residues themselves andwill show an enhanced anti-oxygenic activity when added to oils followed by similarly be treated with the spice residues followed by an elevated temperature treatment to enhance the antioxygenic efiect.

The spice residues also exert an enhanced antioxygenic effect when added in small proportions to the substantially non-volatile, high molecular weight, hydrocarbon oils and particularly the lubricating oils followed by temperature treatments of over 250 F.. and preferably between 350 F. and 500 F.

In carrying out the above described high temperature treatment, it is important that the solids ofthe spice residue be uniformly dispersed or distributed throughout the body of the. oil in substantially fine particles and that the heating be carried'out withsubstantial exclusion of the atmosphere or without contact with air.

It is moreover desirable for the spice residue 1 to be maintained in dispersed condition during 250 F. and a highly stabilized glyceride oil prod- I not will be obtained.

It has been found most important to use the corn oil as expressed from the dry milled germ and which corn oil has not been subjected to any of the usual refining processes.

Although it is desirable to use clove and cinnamon residues which have been substantially exhausted of their oil content, other spice residues may be employed'including the residues obtained following the removal of a substantial proportion of the oils and aromatic constituents from nutmeg, pepper. mustard, paprika, ginger, mace, car away and other spice materials.

Together with or in lieu of the spice residues, there may also be employed their extracts and particularly those extracts obtained by the use of an alcohol soluble solvent. The extracts are desirably chosen from a solvent having the formula XOH where X is hydrogen or a low molecular weight aliphatic group. There may be particularly utilized methyl alcohol, ethyl alcohol, propyl alcohol or butyl alcohol.

The extracts may be prepared by immersing the finely divided residues in the solvent such as in methyl alcohol, using about from 5 to 15 parts of alcohol to each part of residue, agitating for from 5 minutes to 1 hour at a slightly elevated temperature, filtering out or otherwise removing the alcohol containing the dissolved extracted material, and then removing the alcohol, preferably under reduced pressure, whereby the exthe heat treatment and so that the spice residue will not tend to settle or conglomerate or be present in the form of large lumps or particles since in the latter case the fully desirable results of the present invention are not obtained.

It is desirable that the oil after treatment in accordance with the present invention will not be materially changed in its odor or flavor. The oil will, however, have a darker color which may be removed by subjecting it to a bleaching operation.

The spice residues may where desired be subjected to boiling or treatment with acid such as by boiling clove residue in a 2'% acetic acid solution for a period of from 20 minutes to 4 hours,

' followed by neutralization and drying and then utilized in accordance with the present invention. The spice residues may also be first treated with saturated or superheated steam under pressure or under vacuum at temperatures substantially above 250 F., particularly in an acid medium having a pH of less than 6 and preferably less than 4.5. Such residues may then be utilized in accordance with the present invention.

It has also been found that desirable results are obtained where the finely divided spice residues are mixed with the oil or fibrous materials containing the glyceride oil and then the oil is heated to a temperature of, say, from 250 F. to 500 F. under a highly reduced pressure, such as under a gas pressure less than 1 pound per square inch to cause distillation of part or all of the glyceride oil composition and it has been observed that such distilled fraction is highly stable and is also free of the finely divided residue which has served as the stabilizing agent at the elevated temperature of distillation.

There may also be utilized in place of or together with the spice residues and included therewith various types of roots and particularly those used for making therapeutic or flavoring ex tracts, particularly after extraction with water, alcohol, ether or other solvents. For example,

licorice, ginger, angelica, musk, gentian, belladonna, or ergot roots may be utilizedfor addition to oils followed by heating to over 250 F. in accordance with the present invention.

The present application is a continuation in part of application Serial No. 247,631 filed December 24, 1938.

Having described my invention, what I claim is- 1. A process of stabilizing oils subject to oxidative deterioration whereby they become less subject tosuch deterioration which comprises dispersing a small amount of a material selected from the group consisting of the finely divided.

spice residues and their alcohol soluble extracts in the oil and heating the oil to a temperature in excess of 250 F.

29A process of stabilizing'glyceride oils subjec to oxidative deterioration whereby they become less subject to such deterioration which comprises dispersing a small amount of a material selected from the group consisting of the finely divided spice residues and their alcohol soluble extracts in the oil and heating the oil' to a temperature in excess of 250 F.

3. A process of stabilizing substantially unsatoration whereby they become less subject to such 1 deterioration which comprises dispersing a small amount of a finely divided spice residue in the oil and heating theoil to a sufliciently high temperature to char the residue while the oil is under sub-atmospheric pressure, and then filtering off the residue.

- a 5. A stabilized oil normally subject to oxidative deterioration carrying the reaction product of a material selected from the group consisting of the finely divided spice residues and their alcohol soluble extracts in the oil, said reaction product having been formed byv heating a small amount of the materialin the oil to a temperature in excess of 250 F. whereby an enhanced stabilizing effect on the oil is obtained.

6. A stabilized glyceride oil normally subject to oxidative deterioration carrying the reaction productofi a material selected from the group consisting of the finely divided spice residues and their alcohol soluble extracts in the oil, said reaction product having been formed by heating a small amount of the material in the oil to a temperature in excess of 250 F. whereby an enhanced stabilizing effect on the oil is obtained.

7. A glyceride oil normally subject to oxidative deterioration carrying the reaction product of a spice residue in the glyceride oil, said reaction product having been formed by heating a small amount of the spice residue in the oil to a temperature inexcess of 250 F. whereby an enhanced stabilizing effect on the oil is obtained.

8. A glyceride oil normally subject to oxidative deterioration carrying the reaction product of a clove residue in the glyceride oil, said reaction product having been formed-by heating a small amount of the clove residue in the oil to a temperature-in excess of 250 F. whereby an enhanced. stabilizing effect on the oil is obtained. 9. A glyceride oil normally subject to oxidative deterioration carrying the reaction. product of a cinnamon residue in the glyceride oil, said reaction product having been formed by heating asmall amount of the cinnamon residue in the oil to a temperature in excess of 250'F. whereby an enhanced stabilizing effect on the oil is obtained. SIDNEY MUSHER. 

